In recent years, a technique related to a Multipath TCP (MPTCP) which performs transmission of a packet using a plurality of communication paths in a communication network is being developed (refer to NPL 1). According to the MPTCP, there are advantages such as improvement of transmission rate or improvement in stability of communication for using a plurality of TCP connections (communication paths) with respect to one session.
In the related art, as a communication method for improving security in a packet communication between a transmitter side and a receiver side which are connected with each other through a communication network, for example, a technique in which after original data is divided into to be stored a data unit in a packet, and the packet is assembled by giving a pseudo packet identifier for indicating a scrambled packet sequence to the packet, and then the packet is transmitted through a network in the scrambled packet sequence based on the pseudo packet identifier is known (refer to PTL 1).